Process for the production of acetaldehyde and acetone



United States Patent I 3,086,052 PROCESS FOR THE PRODUCTION OF ACETALDE- HYDE AND ACETONE .lurgen Smidt, Munich-Solln, Reinhard Jira, Munich- Pasing, and Walter Hafner, Josef Sedlmeier, and Alois Maier, Munich, Germany, assignors to Consortium fiir Elektrochemische Industrie G.m.b.H., Munich Germany NoDrawing. Filed Nov. 28, 1958, Ser. No. 776,721 Claims priority, application Germany Dec. 2, 1957 -8 Claims. (Cl. 260-597) The present invention relates to a process for the production of acetaldehyde or respectively acetone from acetylene containing ethylene or respectively propylene.

Processes are described for the production of aldehydes and ketones in US. applications Serial No. 744,011, filed June 23, 1958, Serial No. 750,107, filed July 22, 1958, and Serial No. 750,571, filed July 24, 1958, in which hydrocarbons containing one or more olefinically unsaturated double bonds are reacted with aqueous solutions of platinum metal compounds in the presence of oxidizing agents, such as oxygen, iron III and copper II salts.

It is not necessary that pure olefinic hydrocarbons be employed in such processes, as they can also be carried out using technical gas mixtures. For example, the presence of saturated hydrocarbons, nitrogen, carbon dioxide and other inert gases is harmless. Furthermore, the presence of hydrogen and carbon monoxide hardly disturbs such processes.

On the other hand, when acetylene containing technical hydrocarbons are employed in such processes, the conversion of aldehydes and 'ketones is diminished, as a portion of the active platinum metal compounds is blocked by the acetylene. Acetylene is found as an impurity above all in technical ethylene and also under circumstances in technical propylene.

According to the invention it was unexpectedly found that acetylene containing olefinic hydrocarbons can be employed without impairing the reaction when acid aqueous catalyst solutions are employed which in addition to the platinum metal compounds and oxidizing agent, preferably, ferric or cupric salts, also contain mercury salts, preferably, mercuric sulfate. In this way it is possible to provide for a disturbance free conversion of the olefines and in addition the acetylene content is also hydrated to acetaldehyde.

It is already known that acetylene reacts with aqueous solutions of mercury salts with the production of acetaldehyde. It was, however, not to be expected that this reaction would proceed undisturbed alongside of the conversion of the olefinic hydrocarbons. This, in fact, is only the case when acetylene contents up to several percent, about 8 vol. percent, are present in the olefines. Preferably, the acetylene content is not greater than about vol. percent. For most purposes this limitation is of no consequence, as the acetylene content of technical olefinic hydrocarbons in most instances is within this range.

The quantity of mercuric salt required in the catalyst solution depends upon the quantity of acetylene contained in the olefine and must be the higher the higher the acetylene content. For example, with an acetylene content of about 8 vol. percent, about 3 g. of HgSO per liter are required. A quantity of mercury salt in excess of this quantity can be employed but provides no additional advantage. When the acetylene content in the olefine is lower, for example, about 0.7 vol. percent, the quantity of mercuric salt required is only about 1 g. per liter. The molar ratio of platinum metal to mercury can be 1:1, preferably such ratio is between 2:1 and 5:1.

residual gases and the latter recycled to the tower.

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The process according to the invention is preferably carried out at temperatures between 50 and 170 C. and at pressures between 1 and 50 atmospheres.

It was also found that olefines with an acetylene content greater than 8 vol. percent can be employed as starting materials for an undisturbed conversion to aldehydes and ketones, if such starting mixture is pretreated with aqueous acid solutions of mercury salts which, if desired, can also contain oxidizing agents, particularly Fe III salts, to lower the acetylene content to within the limits indicated before being subjected to conversion with the platinum metal compound containing catalyst.

In view of the great affinity of mercury salts for olefines it is rather surprising that such pretreatment does not give rise to disadvantageous olefine losses for the fol lowing conversion. In such pretreatment the acetylene is extensively hydrated to acetaldehyde which can be recovered in a known manner from the pretreating solution. The subsequent actual conversion of the olefines can then be carried out without difiiculty.

This embodiment of the invention is especially advantageous when pyrolysis gases which in addition to ethylene contain substantial quantities of acetylene are employed as starting materials, as complicated separation procedures can be avoided thereby.

Oxygen or other oxygen containing gases can be permitted to act upon the platinum metal compound solutions either together with the acetylene containing olefines or separately therefrom. In addition, the process conditions described in applications Serial No. 750,107, filed July 22, 1958, Serial No. 750,570, filed July 24, 1958, Serial No. 750,571, filed July 24, 1958, and Serial No. 768,861, filed October 22, 1958, can also be employed in connection with the process according to the present invention. I

The following examples will serve to illustrate several embodiments of the process according to the invention.

Example 1 A gas mixture composed of 95 vol. percent C H 2 vol. percent C H and 3 vol. percent C H was reacted at 95 C. countercurrently with a catalyst solution containing 5.3 g. PdCl 231 g. =Fe (SO .9H O, S g. HgSO, and 100 g. H per liter in a wash tower filled with Raschig rings. The acetaldehyde formed was carried out of the tower with the residual unconverted gases which contained no noteworthy quantities of acetylene. The acetaldehyde was washed out from these The catalyst solutionwas regenerated periodically after its activity had diminished by treatment with oxygen and nitrogen oxygen compounds in the absence of olefines as described in applications Serial No. 750,570 and Serial No. 750,571.

Almost the same results were obtained when the catalyst solution only contained 2 g. HgSO per liter rather than 5 g.

Example 2 A gas mixture composed of 50 vol. percent of C H 47 vol. percent C H and 3 vol. percent C H was washed at C. countercurrently with a solution containing 3 g. HgSO g. F2(SO4)39H2O and g. H2804 Per liter whereby the acetylene content of the gas mixture was reduced to less than 1 vol. percent by conversion to acetaldehyde. The acetaldehyde entrained with the treated gas mixture was washed out and the remainder which primarily consisted of ethylene was then passed through a second spray tower and washed at 95 C. countercurrently with a solution containing 17.8 g. PdClg, 231 g. Fe (SO -9H O, 2 g. HgSO and g. H 80 a per liter. The acetaldehyde contained in the residual gases leaving the top of such tower was scrubbed out and the remaining gases recycled to the second tower. The regeneration of each catalyst solution was effected in the same manner but separately from each other with nitric acid and air.

Substantially the same results were obtained when the second catalyst solution contained only 1 g. per liter of HgSQ; instead of 2 g.

Example 3 A gas mixture containing 80 vol. percent of C H 3 vol. percent C H 1 vol. percent C H and 16 vol. percent of was passed at 95 C. through a tower containing an aqueous solution containing 4.5 g. PdCl 16.2 g. FeC1 100 g. CuCl -2H O, 80 g.

CH(CH3CO2) 2 H20 5 g. HgSO and 14.5 g. HCl per liter. The yield of acetaldehyde based upon the ethylene introduced emained constant at 3035%, whereas in the absence of the HgSO, the yield rapidly diminished in view of the precipitation of a Pd-C H compound.

Substantially the same results were obtained when the catalyst solution contained only 2 g. HgSO per liter.

Example 4 A gas mixture consisting of 92 vol. percent of ethylene, 5 vol. percent of acetylene and 3 vol. percent of ethane was converted at 95 C. in a Raschig ring filled spray tower with an aqueous solution containing 17.8 g. PdCl 231 g. Fe (SO -9H O, 3 g. HgSO, and 100 g. H 80 per liter. The acetaldehyde which was produced in a yield of over 95% was recovered as described in Example l and the catalyst solution was periodically regenerated by the methods described in applications Serial No. 750,570 and Serial No. 750,571.

Example 5 A gas mixture consisting of 96 parts by volume of propylene, 4 parts by volume of propane and 0.7 part by volume of acetylene was converted as described in Example l with an aqueous catalyst solution containing 5.3 g. PdCl 231 g. Fe (SO '9I-I O, 1 g. HgCl and 100 g. H 50 per liter. After separation of the acetone formed the catalyst solution was regenerated as described in applications Serial No. 750,570 and Serial No. 750,571.

We claim:

1. A process for the production of a carbonyl compound selected from the group consisting of acetaldehyde and acetone from acetylene-containing gas mixtures, in which the acetylene content is up to 8 vol. percent, selected from the group consisting of acetylene-containing ethylene gas mixtures and acetylene-containing propylene gas mixtures which comprises contacting such gas mixtures with an acid aqueous catalyst solution of a palladium salt, a mercuric salt and an oxidizing agent selected from the group consisting of ferric and cupric salts at a temperature between 50 and C., all of said salts in said solution being in a form selected from the group consisting of chlorides, sulfates and acetates.

2. The process of claim 1 in which the molar ratio of palladium to mercury in said catalyst solution is between 1:1 and 5:1.

3. The process of claim 2 in which the mercuric salt content of the catalyst solution is proportionate to the acetylene content of the gas mixture, at least 3 g. of mercury per liter being provided for an acetylene content of 8%.

4. The process of claim 1 in which said mercuric salt is mercuric sulfate.

5. The process of claim 1 in which the gas mixture contacted with the catalyst solution also contains oxygen.

6. The process of claim 1 in which said process is carried out at a pressure between 1 and 50 atmospheres.

7. A process for the production of a carbonyl compound selected from the group consisting of acetaldehyde and acetone from acetylene-containing gas mixtures in which the acetylene content is over 8 vol. percent selected from the group consisting of acetylene-containing ethylene gas mixtures and acetylene-containing propylene gas mixtures which comprises reacting such gas mixtures with an acid aqueous solution of a mercuric sulfate to reduce the acetylene content thereof to not over 8 vol. percent and then contacting such gas mixtures with an acid aqueous catalyst solution of a palladium salt and a mercuric salt in the presence of an oxidizing agent selected from the group consisting of ferric salts and cupric salts at a temperature between 50 and 170 C., all of said salts in the acid aqueous catalyst solution being in a form selected from the group consisting of chlorides, sulfates and acetates.

8. The process of claim 7 in which said aqueous mercuric sulfate solution employed to reduce the acetylene content of the gas mixtures also contains ferric sulfate.

References Cited in the file of this patent UNITED STATES PATENTS 1,999,620 Van Peski et al Apr. 30, 1935 2,690,457 Hackmann Sept. 28, 1954 FOREIGN PATENTS 713,791 Germany Nov. 14, 1941 891,209 France Nov. 29, 1943 388,402 Great Britain Feb. 24, 1933 OTHER REFERENCES Phillips: Amer. Chem. Jour., vol. 16, pages 255-277 (pp. 265-72 relied upon) (1894).

Chatt: Chem. Abstracts, vol. 48, page 5067 (1954). (Copies of above in Sci. Library.) 

1. A PROCESS FOR THE PRODUCTION OF A CARBONYL COMPOUND SELECTED FROM THE GROUP CONSISTING OF ACETALDEHYDE AND ACETONE FROM ACETYLENE-CONTAINING GAS MIXTURES, IN WHICH THE ACETYLENE CONTENT IS UP TO 8 VOL. PERCENT, SELECTED FROM THE GROUP CONSISTING OF ACETYLENE-CONTAINING ETHYLENE GAS MIXTURES AND ACETYLENE-CONTAINING PROPYLENE GAS MIXTURES WHICH COMPRISES CONTACTING SUCH GAS MIXTURES WITH AN ACID AQUEOUS CATALYST SOLUTION OF A PALLADIUM SALT, A MERCURIC SALT AND AN OXIDIZING AGENT SELECTED FROM THE GROUP CONSISTING OF FERRIC AND CUPRIC SALTS AT A TEMPERATURE BETWEEN 50 AND 170*C., ALL OF SAID SALTS IN SAID SOLUTION BEING IN A FORM SELECTED FROM THE GROUP CONSISTING OF CHLORIDES, SULFATES AND ACETATES. 